1. Field of the Invention
This invention relates to still video recording/playback apparatus and, more particularly, to such apparatus wherein an audio signal may be recorded on a disk at virtually any time following the recording thereon of a still video picture.
2. Description of the Prior Art
Electronic still cameras are known in which a still picture is recorded as a video signal on a magnetic disk. The "instantly recorded" picture may be played back with the use of a playback adapter and displayed, either as a video picture on a television monitor or as a "printed" hard copy picture. While the camera alone is used to record a still video picture on the disk, successful play back is accomplished by connecting the camera to the aforementioned playback adapter. The camera reproduces signals from the disk; and these reproduced signals are processed by the adapter into conventional television signals for display on a conventional television monitor.
Recently, improvements to the still video camera have been proposed, wherein audio signals which relate to the still picture may be recorded on the same disk. For example, a brief narrative explaining the picture, the subjects, the environment, etc., may be recorded as an audio signal and may be linked to the still video picture such that, when the video picture is played back, the recorded narrative likewise may be reproduced. In, for example, Japanese Laid-Open Patent Publication No. 62-99972 and in Japanese Laid-Open Patent Publication No. 62-95079, an audio signal spoken for a predetermined duration (e. g. on the order of five seconds, or ten seconds, or twenty seconds) may be time-base compressed and then recorded in a track on the same disk as was used for recording the still video picture Advantageously, the audio signal is recorded after the recording of the still picture; and this post-recording (or, as is sometimes used herein, the after-recording) process may be carried out immediately after the still video picture is recorded or at a later time, such as when the still video picture is reproduced and displayed.
In the aforementioned audio recording still video camera, the time limit during which the user may record his audio signal is on the order of about ten seconds. That is, an audio signal duration of ten seconds may be recorded. However, if the user does not successfully complete his audio recording in this time limit, for example, if the user does not compose his thoughts successfully, or if the user becomes "tongue-tied", the ten second duration may expire before the user completes his audio recording. It is expected that, during normal operation of the audio recording still video camera, incomplete or unsuccessful audio recording will not be uncommon. In the still video camera proposed heretofore, means are not provided for erasing the incomplete (or unsuccessful) audio signal to enable a subsequent audio recording to be made. It is, therefore, desirable to erase the audio signal from the disk or, for those audio recording still video cameras that employ a memory chip to store temporarily the audio signal, as may be used for time-base compression, to erase the audio signal from memory.
The camera proposed heretofore also does not enable the user of the audio recording still video camera to interrupt an audio recording operation and instantly record a still video picture if the opportunity arises. Heretofore, when an audio recording operation was initiated, it normally had to be completed before a video picture recording operation could begin. Thus, a momentary photographic opportunity may be lost.
In a typical audio recording still video camera, a built-in microphone is provided in the camera housing to facilitate audio recording. However, since the microphone is housed in the same case as the mechanical assemblies which are used in the video and audio signal recording operations, namely, the disk drive, mechanical noises generated by the assemblies are likely to be picked up by the microphone when an audio recording operation is carried out. It is desirable to avoid, or at least minimize such mechanical noises by interrupting the disk drive operation when an audio signal is supplied to the microphone. For example, for the embodiment wherein the audio signal is stored temporarily in a solid-state memory, operation of the disk drive may be interrupted while the audio signal is written into the memory and then resumed when the audio signal is read out and recorded. However, this interruption of the disk drive is not satisfactory when the audio signal is recorded while displaying a video signal. In that event, continual operation of the disk drive is needed to reproduce the still video picture signal from the disk. If the disk drive is stopped so as to minimize mechanical noises, the video signal terminates, thus blanking the displayed video picture and making it difficult, if not impossible, for the user to provide an acceptable narrative of that picture.